The present invention relates to a high frequency power amplifier module having a plurality of amplifying systems, for example, a high frequency power amplifier device (high frequency power amplifier module) capable of performing linear amplification and non-linear amplification (saturation amplification) and a wireless communication apparatus in which the high frequency power amplifier module is built therein, and particularly to a technology effective for application to a cellular portable phone of a multi-mode and multi-band communication scheme or system, which has a plurality of communication functions different from one another in communication mode and frequency band.
In a North American cellular market, a single cellular phone, a so-called dual mode portable phone has recently been used wherein a digital system such as an analog type AMPS (Advanced Mobile Phone Service) covering the whole of North America, which has heretofore been used, TDMA (Time Division Multiple Access), CDMA (Code Division Multiple Access) or the like is built therein.
On the other hand, a GSM (Global System for Mobile Communication) system using a TDMA technology and an FDD (Frequency Division Duplex) technology has been used in Europe or the like. An EDGE (Enhanced Data Rates for GSM Evolution) system has been developed as a communication system in which a transfer rate can be made high in the GSM system.
The EDGE has been described in xe2x80x9cNikkei Electronicsxe2x80x9d published by Nikkei Business Publications, Inc., the Nov. 15, 1999 (no.757), P131, and the Jul. 3, 2000 (no.773), P126 to P139 of the same issue.
The former reference has described a speeded-up mobile communication service in various parts of the world. The present reference describes that the mobile communication service transitions from the second generation of xcx9c9.6 kbits/second to the third generation of xcx9c2 Mbits/second. Further, the reference describes that in Europe, the mobile communication service transitions to an EDGE (third generation) through a GPRS (General Packet Radio Service: 2.5th generation) corresponding to a data communication service based on packet communications in which the existing GSM network is expanded, whereas in the USA, the mobile communication service transitions from an IS-136 system (TDMA) to the EDGE and from an IS-95 system (CDMA) to a cdma2000, an IS-2000 and an HDR (High Data Rate).
The latter reference describes a size reduction in a wireless circuit of a cellular phone. Further, the reference describes that a control technology wherein a plurality of channels can simultaneously be used in a high-speed data transmission or communication service, has been developed, and also describes that in a system EDGE dedicated for a GSM-based data communication service, a modulation scheme is changed from GMSK to eight-phase PSK to increase frequency availability, thereby implementing 384 kbits/second. Furthermore, the same reference discloses a reference board for a GSM cellular phone using a chip set of a superheterodyne system and a direct conversion system.
On the other hand, a multi-mode communication made by a dual mode cellular phone or the like has been described in xe2x80x9cNikkei Electronicsxe2x80x9d published by Nikkei Business Publications, Inc., the Jan. 27, 1997 (no.681), P115 to P126, and xe2x80x9cHitachi Reviewxe2x80x9d published by Hitachi Review Inc., the November 1997 issue, Vol. 79, P63 to P68. The latter reference discloses an offset PLL (Phase-Locked Loop) method or system for the conversion of a transmit frequency on the transmitting side.
While lots of wireless data communications using mobile radio have heretofore been carried out at a transmission rate of 9.6 kbps, accessing to an Internet and corporate databases needs to have a higher transmission rate and hence a communication system corresponding to it has been required. While the GSM system furnishing services with Europe and Asia as principal parts, provides 9.6 kbps-based services under the present situation, an EDGE system in which a transmission rate has been set high, has been developed to meet the above request. Introducing this type of system makes it possible to increase the data transmission rate to 384 kbps and transmit data equivalent to 40 times per unit time to the GSM system.
Another advantage of the EDGE system resides in that since the EDGE system can be introduced by appropriating the basic system of GSM and partly changing a radio modulation system or scheme, it can be operated without introducing infrastructure. This would be attractive for many communication common carriers.
The modulation scheme to be changed serves as a system in which 3xcfx80/8-rotating8PSK (Phase Shift Keying) modulation is used in the EDGE system with respect to GMSK (Gaussian Minimum Shift Keying) modulation of the GSM system. Thus, a signal transmission unit of a wiring apparatus needs to have higher linearity.
Since the EDGE system is a system in which the GSM system has been upbuilt, it is desirable that a single cellular phone is capable of making phone calls through the use of the GSM system and the EDGE system. It is therefore necessary to incorporate an amplifier for the GSM system and an amplifier for the EDGE system in the cellular phone.
The present inventors have discussed a high frequency power amplifier module wherein one amplifier circuit copes with the GSM system and the EDGE system. As a result, the present inventors have found the following problems to be solved.
(1) When the high frequency power amplifier module is used in GSM, the corresponding transistor is used in a saturated operation and hence a large output is required. Namely, an output power of about 36 dBm at maximum is necessary for a GMSK-modulated input signal of about 0 dBm, for example.
(2) When it is used in EDGE, the transistor is used in a linear operation and hence linearity is required for it. Namely, an output signal needs to be undistorted with respect to a 3xcfx80/8-rotating 8PSK-modulated input signal. The maximum of linear output power ranges from about 28 dBm to about 29 dBm.
(3) In the GSM system and the EDGE system, a large difference occurs in their output power as described above as in the case where the maximum power ranges from 6 dBm to 8 dBm, and they differ in amplification class (Class A and Class C). Therefore, when the single amplifier is shared therebetween, lots of noise are produced and controllability becomes low due to the difference in gain therebetween.
An object of the present invention is to provide a high frequency power amplifier module and a wireless communication apparatus, which are capable of causing a saturation-operated system and a linearly-operated system to coexist with each other within the same circuit.
Another object of the present invention is to provide a high frequency power amplifier module and a wireless communication apparatus, which allow a GSM system (saturation operation) and an EDGE system (linear operation) to coexist with each other within the same circuit.
A further object of the present invention is to provide a high frequency power amplifier module and a wireless communication apparatus, which have plural modes/plural bands configurations.
The above, other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
Summaries of typical ones of the inventions disclosed in the present application will be described in brief as follows:
(1) There is provided a high frequency power amplifier module comprising:
an input terminal supplied with a signal to be amplified;
an output terminal;
a control terminal;
a mode switch terminal;
a plurality of amplifying stages cascade-connected between the input terminal and the output terminal,
the plurality of amplifying stages respectively comprising first terminals each of which receives a signal inputted to each amplifying stage, second terminals each of which transmits a signal outputted therefrom, and third terminals each of which receives a reference potential for each amplifying stage;
bias circuits which are respectively connected between the control terminal and the first terminals of the respective amplifying stages and respectively apply to the first terminals a dc bias potential based on a voltage supplied to the control terminal;
a plurality of temperature characteristic compensating circuits which respectively constitute current mirror circuits with respect to the respective amplifying stages; and
a mode switching circuit which is operated by a signal supplied to the mode switching terminal and turns on and off each temperature characteristic compensating circuit to thereby perform switching between communication modes,
wherein the one or more amplifying stages excluding the amplifying stage corresponding to a final stage, of the plurality of amplifying stages, and the temperature characteristic compensating circuits corresponding to the one or more amplifying stages respectively comprise load-side semiconductor amplifying elements and ground-side semiconductor amplifying elements connected in series, control terminals of the load-side semiconductor amplifying elements of the amplifying stages and control terminals of the load-side semiconductor amplifying elements of the temperature characteristic compensating circuits corresponding to the amplifying stages are respectively connected to one another, and each of control terminals of the ground-side semiconductor amplifying elements of the amplifying stages is connected between resistors forming a voltage dividing resistor of each of the bias circuits for the amplifying stages,
a selected and fixed potential is applied to the control terminal of the load-side semiconductor amplifying element of each amplifying stage in one communication mode (EDGE mode) so that the communication modes different from each other approximate each other in gain, and
predetermined fixed potentials are respectively applied to the first terminals of the respective amplifying stages as bias potentials.
The high frequency power amplifier module is switched to either a phase-modulation circuit configuration (circuit configuration for a saturation amplifier, e.g., circuit configuration for GSM) or a phase and amplitude-modulation circuit configuration (circuit configuration for a linear amplifier, e.g., circuit configuration for EDGE) according to the operation of the mode switching circuit. The load-side semiconductor amplifying elements and the ground-side semiconductor amplifying elements are dual gate type semiconductor amplifying elements.
As a specific configuration, the plurality of amplifying stages, the bias circuits and the temperature characteristic compensating circuits incidental thereon, and the mode switch terminal are provided in plural form to thereby constitute a plurality of amplifying systems. The respective amplifying stages are connected to such mode switching terminals to constitute a multi-mode and multi-band high frequency power amplifier device or module.
For example, the high frequency power amplifier module takes a dual-band configuration having two amplifying systems. Each of the amplifying systems is formed as a dual-mode configuration corresponding to the configuration described in the above (1). Thus, the high frequency power amplifier module comprises a GSM900, a GSM1800 and an EDGE operated according to switching. External electrode terminals of the high frequency power amplifier module include input terminals (Pin-GSM900 and Pin-GSM1800), output terminals (Pout-GSM900 and Pout-GSM1800), control terminals (Vapc-GSM900 and Vapc-GSM1800), first reference potentials (Vdd-GSM900 and Vdd-GSM1800), a second reference potential (GND), first terminals (Vcgs-GSM900 and Vcgs-GSM1800) of load-side semiconductor amplifying elements, and a mode switching terminal (mode-SW).
Such a high frequency power amplifier module is incorporated in a transmission system of a wireless communication apparatus.
(2) In an EDGE mode under the configuration described in the above (1), an APC (automatic output control) signal is applied to each of the control terminals of the load-side semiconductor amplifying elements of the amplifying stages, and predetermined fixed potentials are respectively applied to the first terminals of the respective amplifying stages as bias potentials.
Such a high frequency power amplifier module is incorporated in a wireless communication apparatus as a direct conversion method or system or an offset PLL method or system. In the offset PLL method, the high frequency power amplifier module directly inputs an amplitude-modulated signal to its corresponding first gate of a dual gate transistor of a first-stage amplifying stage and directly inputs a phase signal to its corresponding second gate thereof.
(3) In the EDGE mode under the configuration described in the above (1), an APC signal is applied to each of the control terminals of the load-side semiconductor amplifying elements of the amplifying stages, and APC signals are respectively applied to the first terminals of the respective amplifying stages as bias potentials.
(4) There is provided a high frequency power amplifier module for performing a linear amplifying operation or a non-linear amplifying operation according to a communication mode signal, comprising:
an input terminal supplied with a signal to be amplified;
an output terminal;
a mode switch terminal;
a plurality of amplifying stages cascade-connected between the input terminal and the output terminal and having first terminals for respectively receiving input signals supplied to the amplifying stages, and second terminals for respectively sending out signals outputted from the amplifying stages;
bias circuits which are respectively connected to the first terminals of the respective amplifying stages and apply bias potentials to the first terminals; and
a mode switching circuit which forms a mode signal according to a communication mode signal supplied to the mode switch terminal;
wherein at least one amplifying stage of the plurality of amplifying stages includes first and second semiconductor amplifying elements series-connected to one another, the first terminal of the amplifying stage is connected to a control input node of the second semiconductor amplifying element, and the second terminal thereof is connected to an output node of the first semiconductor amplifying element,
the mode signal is supplied to the control input node of the first semiconductor amplifying element, and
when the linear amplifying operation and the non-linear amplifying operation are performed, gain is controlled by the mode signal.
(5) There is provided a high frequency power amplifier module comprising:
an input terminal supplied with a signal to be amplified;
an output terminal;
a mode terminal;
a plurality of amplifying stages cascade-connected between the input terminal and the output terminal and having first terminals for respectively receiving input signals supplied to the amplifying stages, and second terminals for respectively sending out signals outputted from the amplifying stages;
bias circuits which supply bias potentials to the respective amplifying stages respectively; and
a mode circuit which forms an AGC signal according to a signal supplied to the mode terminal;
wherein at least one of the amplifying stages has first and second semiconductor amplifying elements series-connected to one another, and
a control terminal of the first semiconductor amplifying element is supplied with the AGC signal, an output terminal of the first semiconductor amplifying element is connected to the corresponding second terminal, and a control terminal of the second semiconductor amplifying element is connected to the corresponding first terminal.
(6) There is provided a high frequency power amplifier module comprising:
an input terminal supplied with a signal to be amplified;
an output terminal;
a mode terminal;
a plurality of amplifying stages cascade-connected between the input terminal and the output terminal and having first terminals for respectively receiving input signals supplied to the amplifying stages, and second terminals for respectively sending out signals outputted from the amplifying stages;
bias circuits which supply bias potentials to the respective amplifying stages respectively; and
a mode circuit which forms an APC signal according to a signal supplied to the mode terminal;
wherein at least one of the amplifying stages has first and second semiconductor amplifying elements series-connected to one another, and
a control terminal of the first semiconductor amplifying element is supplied with the APC signal, a control terminal of the second semiconductor amplifying element is connected to the corresponding first terminal and an output terminal of the first semiconductor amplifying element is connected to the corresponding second terminal.
According to the means described in the above (1), (a) in an EDGE mode, a selected and determined fixed potential is applied to each of the control terminals of the load-side semiconductor amplifying elements of the amplifying stages, an AGC signal is inputted to the input terminal, and potentials between the first terminals and third terminals of the respective amplifying stages are respectively fixed to predetermined values, whereby the gain in the EDGE mode can be controlled or suppressed while an adjacent channel leakage power standard is being satisfied, and the gains in the communication modes (GSM mode and EDGE mode) different from each other can be rendered approximate, thereby allowing stable multi-mode communications.
(b) It is possible to maintain a GSM 0 dBm input (three-stage configuration) widely used in GSM/EDGE dual modes. It is not necessary to increase a VCO output or newly introduce a pre-amplifier.
According to the means described in the above (2), (a) in an EDGE mode, an APC signal is applied to each of the control terminals of the load-side semiconductor amplifying elements of the amplifying stages, a fixed predetermined signal is inputted to the input terminal, and potentials between the first terminals and third terminals of the respective amplifying stages are respectively fixed to predetermined values, whereby the gain in the EDGE mode can be controlled or suppressed while an adjacent channel leakage power standard is being satisfied, and the gains in the communication modes (GSM mode and EDGE mode) different from each other can be rendered approximate, thereby enabling stable multi-mode communications.
(b) A direct conversion method or system eliminates the need for an AGC circuit, and a reduction in the manufacturing cost of a wireless communication apparatus can be achieved owing to a reduction in the number of components.
(c) An offset PLL method or system eliminates the need for the AGC circuit, and a reduction in the manufacturing cost of a wireless communication apparatus can be achieved owing to a reduction in the number of components.
(d) In the offset PLL method, the high frequency power amplifier module has a mixer function and makes it unnecessary to provide a mixer as a discrete circuit. Thus, a reduction in the manufacturing cost of a wiring communication apparatus can be achieved owing to a reduction in the number of components.
According to the means described in the above (3), (a) in an EDGE mode, an APC signal is applied to each of the control terminals of the load-side semiconductor amplifying elements of the amplifying stages, a fixed predetermined signal is inputted to the input terminal, and potentials between the first terminals and third terminals of the respective amplifying stages are respectively controlled by APC signals, whereby the gain in the EDGE mode can be controlled or suppressed while an adjacent channel leakage power standard is being satisfied, and the gains in the communication modes (GSM mode and EDGE mode) different from each other can be rendered approximate, thereby enabling stable multi-mode communications.